Abstract: Objective: This study aimed to explore high-efficiency aroma-producing functional strains from the stacked fermented grains of Jiangxiang Baijiu, systematically analyze their biological characteristics, environmental tolerance, and brewing functions, and further provide scientific data support for the development of Baijiu microbial strain resources and the optimization of flavor quality. Methods: Strains were isolated from the stacked fermented grains of Jiangxiang Baijiu. Strain identification was completed through morphological observation, physiological and biochemical experiments combined with whole-genome sequencing. Gradient stress experiments were used to analyze the strain's tolerance ability. Gas chromatography technology was applied to detect the content of flavor substances of the strain in sorghum juice medium and simulated fermented grain fermentation system, respectively. Finally, Illumina NovaSeq sequencing technology was used for whole-genome sequencing, and functional annotation was conducted to analyze core functional genes. Results: A high-efficiency aroma-producing strain XJ-YDG001-1 was isolated and identified as Geotrichum candidum. This strain could produce floral, fruity, sweet, and acidic aromas, and tolerate 6% ethanol and 8% lactic acid. In the sorghum juice medium fermentation system, strain XJ-YDG001-1 significantly increased the accumulation of ester substances, raising the ester content from the initial (5120.41±58.43) mg/L to (38186.97±158.89) mg/L. Further verification through simulated fermented grain experiments showed that this strain could also effectively promote ester synthesis, increasing the ester content in fermented grains from (60.41±3.86) mg/100 g to (188.65±15.54) mg/100 g. Whole-genome sequencing revealed that the strain had a genome length of 22937131 bp, a GC content of 46.09%, and 6955 predicted protein-coding genes. The results of genomic functional annotation indicated that the strain's genes were highly enriched in metabolism, genetic information processing, and molecular catalytic functions. It also carried key genes such as glycoside hydrolase (GH15) and esterase (CE10), which could participate in the flavor synthesis process of Jiangxiang Baijiu by decomposing substrates and catalyzing precursor substances. Conclusion: Geotrichum candidum XJ-YDG001-1 has excellent aroma-producing ability and environmental tolerance, and has potential application value in the flavor regulation of Jiangxiang Baijiu. This study provides a theoretical basis for the exploration and utilization of functional microorganisms in Baijiu production.